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器件3D模型￥ 3.319
ST890CDR 开发手册 - ST Microelectronics（意法半导体）
制造商:
ST Microelectronics（意法半导体）
分类:
电源管理
封装:
SO-8
描述:
STM系列 SO-8 1.2 A 电流限制 高边 电源开关 带过热关断
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功能描述在P2P3P4P5P6P7P8
应用领域在P13
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ST890CDR数据手册
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Functional description AN1441
2/13 Doc ID 8422 Rev 2
1 Functional description
1.1 Switch resistance
The internal block diagram of the ST890 is shown in Figure 1. The high side power
MOSFET, used as a switch, has an R
ON
lower than 90 mΩ at V
CC
= 3.0 V. In the case of a
load current of 1 A, the drop voltage between the IN and OUT pins is lower than 1 A x 0.1 Ω
= 0.1 V and, for a switch, it is very important to keep this drop voltage low.
Figure 2 displays the R
ON
versus the V
IN
supply voltage. The R
ON
depends on the V
IN
because the P-channel MOSFET is driven by the V
OUT
of the internal error amplifier.
Figure 2. ON resistance vs. V
IN
supply voltage
1.2 Short-circuit protection
The low resistance of the MOS channel is important. However, the control circuitry that must
quickly drive the MOS to provide enough V
GS
voltage to turn on the MOS channel, has
greater importance. If the control circuitry does not drive the MOS quickly enough, the
current of the card could be broken, as shown in Figure 3: ST890 in a short-circuit condition.
65
70
75
80
85
90
95
100
2.5 33.5 4 4.5 5 5.5 6
V
IN
(V)
R
(on)
(m ohm)
T
A
= 25°C
AM00159v1
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